Ionic compounds have nothing to do with magnets. Probably the easiest way to describe an ionic compound is that it will dissociate into ions in water. I'm not sure that there is a way to "recognize" this, however, since you can't see ions. Electrical conductance is very good in ionic solutions, so a strong decrease in electrical resistance of a solution of the compound might be way to recognize it. Keep in mind, however, that some covalent compounds will also increase conductivity, to this test is more quantitative than qualitative.